With changes of global environment, a growing number of people has entered America in recent decades, including immigrants, refugees, exchange students, and visitors. The influx of newcomers has brought great challenges to American public libraries to meet the needs and desires of diverse groups in the community. This paper discusses how public libraries can improve their services and programs for the ethnic, cultural, and linguistic diversities of community members. Especially, this paper comprehensively discusses that the public library's atmosphere for newcomers, community need assessment, library services and programs, multicultural collections, multicultural staff, collaboration with other organizations and groups, information and communication technology, and future challenges for public libraries.